#include <stdio.h>
#include <string.h>
#define FILE_NAME "log.txt"
int main()
{
    FILE* fp = fopen(FILE_NAME, "w+");
    if(fp == NULL)
    {
        perror("FILE");
        return 1;
    }
    fputs("Hello world\n", fp);
    fclose(fp);
    return 0;
}
